Classifications

• • D—TEXTILES; PAPER
  • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
  • D21H—PULP COMPOSITIONS; PREPARATION THEREOF NOT COVERED BY SUBCLASSES D21C OR D21D; IMPREGNATING OR COATING OF PAPER; TREATMENT OF FINISHED PAPER NOT COVERED BY CLASS B31 OR SUBCLASS D21G; PAPER NOT OTHERWISE PROVIDED FOR
  • D21H19/00—Coated paper; Coating material
  • D21H19/80—Paper comprising more than one coating
  • D21H19/84—Paper comprising more than one coating on both sides of the substrate
• • D—TEXTILES; PAPER
  • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
  • D21H—PULP COMPOSITIONS; PREPARATION THEREOF NOT COVERED BY SUBCLASSES D21C OR D21D; IMPREGNATING OR COATING OF PAPER; TREATMENT OF FINISHED PAPER NOT COVERED BY CLASS B31 OR SUBCLASS D21G; PAPER NOT OTHERWISE PROVIDED FOR
  • D21H11/00—Pulp or paper, comprising cellulose or lignocellulose fibres of natural origin only
  • D21H11/14—Secondary fibres
• • D—TEXTILES; PAPER
  • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
  • D21H—PULP COMPOSITIONS; PREPARATION THEREOF NOT COVERED BY SUBCLASSES D21C OR D21D; IMPREGNATING OR COATING OF PAPER; TREATMENT OF FINISHED PAPER NOT COVERED BY CLASS B31 OR SUBCLASS D21G; PAPER NOT OTHERWISE PROVIDED FOR
  • D21H21/00—Non-fibrous material added to the pulp, characterised by its function, form or properties; Paper-impregnating or coating material, characterised by its function, form or properties
  • D21H21/50—Non-fibrous material added to the pulp, characterised by its function, form or properties; Paper-impregnating or coating material, characterised by its function, form or properties characterised by form
  • D21H21/52—Additives of definite length or shape
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
  • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
  • Y10T428/00—Stock material or miscellaneous articles
  • Y10T428/25—Web or sheet containing structurally defined element or component and including a second component containing structurally defined particles
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
  • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
  • Y10T428/00—Stock material or miscellaneous articles
  • Y10T428/25—Web or sheet containing structurally defined element or component and including a second component containing structurally defined particles
  • Y10T428/258—Alkali metal or alkaline earth metal or compound thereof
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
  • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
  • Y10T428/00—Stock material or miscellaneous articles
  • Y10T428/25—Web or sheet containing structurally defined element or component and including a second component containing structurally defined particles
  • Y10T428/259—Silicic material
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
  • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
  • Y10T428/00—Stock material or miscellaneous articles
  • Y10T428/27—Web or sheet containing structurally defined element or component, the element or component having a specified weight per unit area [e.g., gms/sq cm, lbs/sq ft, etc.]
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
  • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
  • Y10T428/00—Stock material or miscellaneous articles
  • Y10T428/27—Web or sheet containing structurally defined element or component, the element or component having a specified weight per unit area [e.g., gms/sq cm, lbs/sq ft, etc.]
  • Y10T428/273—Web or sheet containing structurally defined element or component, the element or component having a specified weight per unit area [e.g., gms/sq cm, lbs/sq ft, etc.] of coating
  • Y10T428/277—Cellulosic substrate
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
  • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
  • Y10T428/00—Stock material or miscellaneous articles
  • Y10T428/31504—Composite [nonstructural laminate]
  • Y10T428/31971—Of carbohydrate
  • Y10T428/31993—Of paper

Definitions

• the present invention relates to a web printing paper coated on both sides, consisting of a coating base paper that contains mineral filler and, as fiber components, wood pulp and/or cellulose.
• the coating which contains pigment and binder and serves to absorb the printing ink, is applied by means of a film press.
• the invention also relates to a process for manufacturing the web printing paper.
• Web printing papers of the aforementioned type are used in the production of periodicals, especially illustrated periodicals, magazines, catalogs and advertising brochures, such as those normally inserted into daily newspapers or illustrated periodicals.
• EP-0 377 983 A2 relates to a newsprint paper coated by means of an air brush or a roller coating device, which is said to have improved ink absorption, surface strength and opacity. Coat weights between 1 and 12 g/m 2 , preferably between 3 and 8 g/m 2 , per side to be printed are disclosed, whereby a total grammage of 60 g/m 2 is not exceeded.
• the filter content of the known coating base paper lies in the usual range of between 0.5 and 10% by weight, preferably, however, at less than 0.5% by weight.
• the article “Surface Coated SC Papers, a Challenge for LWC Papers,” relates to coating SC papers with a filler content of 15 to 25%.
• an SDTA application system short dwell time applicator
• the application weights are in the range up to 3.5 g/m 2 per side, while in the case of coating base papers with a lower filler content of less than 10% by weight, higher application weights are required--for example, in the so-called LWC papers, a coating application weight of up to approx. 9 g/m 2 per side.
• the object of the present invention is to provide a web printing paper coated on both sides that can be manufactured under economical conditions, during the manufacture of which, in particular, no double coat is necessary, and the fiber material of which consists, as applicable, of recycled fibers, and the appearance and printability of which are comparable to the standard web printing papers on the market.
• the invention seeks to provide a web printing paper suitable for gravure printing.
• the invention calls for a web printing paper coated on both sides, which consists of a coating base paper that contains mineral filler and, as its fiber components, wood pulp and/or cellulose, wherein the coating, which serves to absorb the printing ink contains pigment and binder, is applied by means of a film press.
• the paper is characterized by the fact that
• the coating base paper has a grammage of 30 to ⁇ 58 g/m 2
• the filler content of the coating base paper, relative to its grammage equals 15 to 35% by weight
• the coating base paper contains, in addition to wood pulp and/or cellulose, up to ⁇ 50% by weight recycled fibers, and all weight parts add up to 100% by weight
• the coating on each side has a grammage of 2 to 12 g/m 2
• the pigment of the coating has a grain size for 40 to 60% by weight of ⁇ 2 ⁇ m
• the web printing paper according to the invention refers exclusively to single-ply papers, in contrast to cardboard, for example.
• Filler refers to the mineral pigments that are added to the fiber suspension during paper manufacture. No distinction is made here between freshly added fillers and fillers that are added to the paper manufacturing process, as applicable, together with fiber material recovered from waste paper.
• Recycled fibers are fiber material recovered from waste paper; according to the invention, especially those fibers are preferred which are recovered from Waste Paper Category D31 on the list of German standard types.
• De-inked recycled fibers are fibers from which the printing ink has been removed to the greatest extent possible.
• Wood pulp refers to wood fibers mechanically reduced in size, i.e., to both the so-called groundwoods and to the types obtained with the help of refiners.
• a list of the various types of wood pulp is found in "Cellulose and Paper” (Zellstoff and Toilet) 37 (1988), p. 212.
• TMP material thermo-mechanical refiner wood pulp
• Wood pulp and cellulose refer to "fresh" fibers, in contrast to recycled fibers based on wood pulp or cellulose.
• film press is used here to identify all devices in which a pre-dosing of the coater is carried out by means of dosing rollers, blades and smooth or ridged rolling blades on a transfer roller, from which the pre-dosed coater is "indirectly” transferred to the base paper web in order to form the coating. Further explanations are contained in the reference materials discussed above: "Paper Manufacturing Weekly” 13 (1992), pp. 507 to 515, as well as “Paper Manufacturing Weekly” 6 (1992), pp. 193 to 197.
• Hot-soft calendars are also known in the profession as soft-compact calendars; the roll gap consists of a hot hard-cast roller and a roller connected thereto with resilient plastic; see also the "Paper Manufacturing Weekly” 16 (1990), pp. 701 to 708.
• All weights of fiber materials, base papers, coated papers and coatings refer to "oven-dried" weights.
• Information on the binder relates to the solid content of the binder.
• one of the known sedimentation processes is used, e.g., pipette, sedigraph or Shimadzu centrifuge.
• the pigments present in the coating according to the invention are exclusively mineral pigments. Due to their relatively coarse grain distribution, such pigments have in the past been added as fillers to the fiber pulp during paper manufacture.
• the inventors have realized that when these coarse-grained pigments are used as coating pigments for a coater to be applied by means of a film press, so-called "film splitting" does not occur or at least occurs to a substantially reduced extent. As a result, a substantially smoother coated surface is created.
• the invention therefore makes it possible, even when highly pigmented coaters are used, to also apply substantially higher coating weights without problems. Good coverage of the surface of the coating base paper is possible with a single coat.
• the pigment of the coat for 40 to 55% by weight has a grain size of ⁇ 2 ⁇ m.
• the coating pigment can contain up to a maximum of 10% by weight (relative to the total pigment content) of one or more non-mineral pigments, e.g., non-dissolved starch granules.
• a web printing paper of high opacity and good surface structure is created that can be printed by the offset as well as the gravure method. It is preferred that the pigment content of the coat, relative to the total fiber content of the coat, equals no less than 80% by weight; standard coater additives may be present in a subordinate maximum amount of 1.5% by weight.
• the use of a film press as the coating device makes it possible to reduce the coating base paper to 30 g/m 2 .
• the coating base paper in conjunction with the pigment composition according to the invention of the coating that serves to absorb the printing ink, it is possible for the coating base paper to use, in addition to wood pulp and/or cellulose, up to a ⁇ 50% by weight share of recycled fibers, preferably de-inked recycled fibers.
• the present invention thus offers, first, the advantage of saving on material costs by using the coating pigments according to the invention, which are more economical than the usual fine-part coating pigments. Furthermore, the advantage of reduced manufacturing costs is achieved by using only a single coating process. Finally, the invention also provides the advantage of being able to use recycled fibers to a considerable extent. The invention is not limited to the use of recycled fibers; rather, because of the reduced material and manufacturing costs, significant economic benefits are achieved even when the fiber material of the coating base paper consists solely of wood pulp and cellulose.
• the coating pigments in order to ensure an even coated surface, it has proved advantageous for the coating pigments to have an average grain size in the range from 1.3 to 2.5 ⁇ m, while their BET surface lies between 6.5 and 9 m 2 /g. Kaolin, calcium carbonate and talcum are preferred as suitable coating pigments.
• the coating pigment to be used according to the invention consists by more than 80% by weight of kaolin, calcium carbonate, talcum or a mixture of these coating pigments in the indicated grain size distribution, while the rest of the coating pigment may consist of the same pigments, but in finer distribution, or of other pigments, e.g., aluminum hydroxide, bentonite or titanium dioxide.
• a coating application of more than 5 g/m 2 per side is preferred; however, the application weight should not exceed 10 g/m 2 per side.
• the binder content of the coat is based on the purpose for which the web printing paper according to the invention will be used.
• a binder content of 12 to 20% by weight, relative to the pigment is preferred.
• a binder content of 10 to 15% by weight is adequate.
• a binder content of 4 to 7% by weight, relative to the pigment is called for according to the invention.
• the binders that can be used include the usual synthetic latexes based on acrylate and butadiene-styrene as well as binders based on starch, especially in the case of offset printing formulas; in this case, it is generally preferred that the binder as a whole consist largely of a synthetic latex. Only in the case of offset printing formulas with binder shares of more than 10% by weight can more than 50% by weight, but not more than 65% by weight, of binder based on starch be used.
• a coating base paper to which cationic starch is added during manufacture as a additive to improve strength has proved suitable.
• the fillers of the coating base paper consist largely of kaolin, calcium carbonate and talcum or a mixture of these substances.
• the manufacture of the web printing paper can take place on-line, i.e., the coating base paper, after drying, is fed directly to the film press for application of the coating and is directly glazed by means of a calendar, as applicable, even without intermediate winding following the application and drying of the coat.
• the calendar used may be a super calendar or a hot-soft calendar.
• Examples 1 and 2 a wood-containing coating base paper with a grammage of 52 g/m 2 and a filler share of 31% by weight was coated in an experimental coating device equipped with a film press (application weight: 6 g/m 2 per side), dried and satinized on a super calendar.

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Cited By (11)

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Citations (7)

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• 1994
  • 1994-04-08 DE DE4411987A patent/DE4411987C2/de not_active Expired - Fee Related
• 1995
  • 1995-04-07 DK DK95916612T patent/DK0754260T3/da active
  • 1995-04-07 AT AT95916612T patent/ATE171743T1/de not_active IP Right Cessation
  • 1995-04-07 EP EP95916612A patent/EP0754260B1/de not_active Expired - Lifetime
  • 1995-04-07 WO PCT/EP1995/001283 patent/WO1995027824A1/de active IP Right Grant
  • 1995-04-07 CA CA 2187182 patent/CA2187182C/en not_active Expired - Fee Related
  • 1995-04-07 ES ES95916612T patent/ES2123976T3/es not_active Expired - Lifetime
  • 1995-04-07 DE DE59503785T patent/DE59503785D1/de not_active Expired - Fee Related
  • 1995-04-07 US US08/722,248 patent/US5952091A/en not_active Expired - Fee Related
  • 1995-04-07 JP JP52607395A patent/JPH09511552A/ja active Pending
• 1996
  • 1996-10-02 FI FI963942A patent/FI963942A/fi unknown

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